Compression tool system



Nov. 9, 1965 w. sUND 3,216,196

COMPRESSION TOOL SYSTEM Filed D90. 31, 1952 2 Sheets-Sheet l FIG. 70 ,!3 +72 4 PIPSSUEE' 50K/ECE 50 F IG. 3

nza' 76 Nov. 9, 1965 w. sUND 3,216,196

COMPRESSION TOOL SYSTEM Filed Deo. 31, 1962 2 Sheets-Sheet 2 V /I l United States Patent O 3,216,196 CMPRESSION TOOL SYSTEM William Sund, Bronx, N.Y., assigner to Burndy Corporation, la corporation of New York Filed Dec. 31, 1962, Ser. No. 248,702 2 Claims. (Cl. 6ll-S1) This invention relates :generally to hydraulically powered lcompression tools, Aand in particular to a novel control system for such tools.

`Compression tools of the type 'adapted for use in applying compressible connectors to electrical power lines, commonly called hotsticks, vare frequently used by an operator while the line is fully energized, at high current or voltage values. To avoid the dangers of shocks and burns -under these conditions, it is desirable to eliminate as far as possible all contacts between the operator and the energized lines. For this reason it yis generally desirable that the controls handled directly by the operator in causing the tool to compress and release connectors on the energized line be electrically isolated from the line `and from the parts of the tool in contact with it. Similarly, it is advantageous to provide means whereby the insulated compression tool may 'be employed in placing -a connector on the l-ine in addition to compressing and releasing it, so as to eliminate the need for the oper- Iator to position the connector directly by hand.

Accordingly, it is an object of this invention to provide a semi-automatic compression tool control system in which control signals are transmitted Via dielectric means.

Another object is to provide a pressure actuated control system for a pressure a-ctuated compression tool wherein two pressure transmitting syste-ms each having independent and distinct pressure transmitting media may be employed;

Still another object is the provision of a control system which may be simply and inexpensively added to standard compression tool systems which employ a pressure fluid reservoir and a fluid pressure pump.

And yet another object is the provision of a simple, and inexpensive control for a pressure actuated compression tool, which enables a compression tool of ordinary design to selectively engage and hold an article without compressing it.

These and other objec-ts, features, and advantages of this invention will be made more apparent by reference to .the following specification taken in -conjunction with the accompanying drawings, in which:

FIGURE 1 is a diagrammatic representation of a compression tool and pressure control system constructed in accordance with this invention.

FIGURE 2 is a detailed side section view of one embodiment of a reservoir and booster pump as in FIG- URE 1;

FIGURE 3 `is a partial section view of the control system ot FIGURE 1 taken to the lright of line 3 3 in FIGURE 1.

Referring now particularly to FIGURE 1, reference numeral designates generally a hydraulic .piston powered compression tool which is connected through iluid passage means .such as flexible tubing 12 to =a pneumatically powered hydraulic booster pump 14. Hydraulic fluid from reservoir 16 passes through passage 18, through the pump 14, and -is transmitted ata given pressure through tubing 12 to produce holding or crimping force between the jaws 20 of the tool. The pump derives motive power, in a manner described subsequently herein, from pressurized air which is supplied under pressure -at inlet 22 and is exhausted, to atmosphere in the embodiment shown, at outlet 24. When the pump is in operation, hydraulic Huid from the reservoir is raised to `a given pressure within the pump and is transmitted 3,2 16,196 Patented Nov. 9, l 965 ICC to the tool through tubing 12 at pump pressure. When the pump is at rest the reservoir chamber is vented to atmospheric pressure, and as a result ,of the pressure difference, the pressurized fluid in `the tool flows back through tubing 12, through the pump 14, and into the reservoir 16 for reuse when the pump is again actuated. If the reservoir chamber is pressurized las by air under pressure forced into the chamber at inlet 26, a series of check valves within pump 14, to be described subsequen-tly, permit the hydraulic fluid to be transmitted at reservoir pressure through the tubing 12 to the tool 10.

The reservoir pressure thus applied to the tool, being less than the developed pump pressure, may be selected to produce a force between the jaws of the 4tool sufficient lto .hold an article without compressing it.

It can now be seen that by selectively venting the reservoir chamber to latmospheric pressure, then applying air pressure directly to the chamber, and then applying air pressure t-o opera-te the booster pump, the hydraulic lluid pressure applied to the compression tool may be Varied to three distinct values solely through control of air pressure. The pressurized Iair, a known dielectric medium, provides a control system which `is eiectively electrically isolated from the hydraulic fluid force applying system.

Two two-way air valves S0 and 51, and three vent or exhaust valves 54, 55 and 56, to the right of line 3-3, comprise generally the novel control system of this invention, which permits selectively applying pressurized air from source 60 to pump 14 and/or reservoir 16 in the `sequence described above.

Air from source 60 is supplied to valve S0 through inlet 62. The valve is selectively movable between ltwo positions in response to operation of vent control valves 54 and 56 which are lconnected through .air passages 74 and 76 t-o `control ports 64 and 66 respectively. In the iirst position air outlet 68 is directly connected to inlet 62 for transmitting air through passage means 70 to pump inlet 22; in the second position inlet 62 is shut off and outlet 68 is vented to atmospheric pressure through eX- haust port 72. Valve 51 operates in identical manner to connect reservoir inlet 26 selectively to air pressure from .source 60 or to atmospheric pressure. The inlet and outlet ports of valve 51 are designated by primed reference numerals corresponding to the identical parts of valve 50. Control valves 55 and 56 lare connected to ports 64 and 66 respectively; operation of valve 56 thus operates valves S0 and 51 simultaneously.

For a booster pump suc-h as that here illustrated, which may require initial pressurization of the Huid in supply reservoir 16, this system follows the sequence described above to `apply pressure to the reservoir prior to actuation of the pump and to maintain pressure until the .pump is stopped. If it is desired to vary the described sequence, a check valve 28 may be coupled as shown between pump pneumatic inlet 22 and reservoir inlet 26. The valve is adapted to permit unidirectional air flow from the pump inlet to the reservoir to assure simultaneous pressurization of the reservoir as the pump starts operation.

In using the tool, an operator thus need contact only the three control valves which may be fully insulated from any conductive portions of the tool power system, including the hydraulic fluid, by use of dielectric material such `as nylon or Teflon for the power and control tubing portions 70, 70', 74. 75 and 76.

In FIGURE 2, the operating portions of the pump 14 and reservoir 16 combination are shown in greater detail. The upper portion of the pump housing may be seen to include a slide valve 30 having a slidable plunger 32. The plunger controls the flow of air pressure from inlet 22 through passage 34 an'd into chamber 36 to drive pneumatic piston 38 downward within cylinder 40 against spring 42. In particular, with slidable plunger 32 in the position shown, i.e. the eXtreme right-hand position, chamber 36 is vented through passage 34, annular valve passage 31C, and the annular chamber defined by the reduced diameter portion 32A of plunger 32, to the atmosphere through atmospheric vent 24 and connected annular passage 31D. Spring 42, unopposed by air pressure in chamber 36, thus maintains the piston 38 in its uppermost position. With the piston in this position the chamber at the left end of the plunger is connected through housing passage 33B, and passage 39A in piston extention 39, to atmosphere through atmospheric vent 24' in chamber 37. When air pressure is supplied at inlet 22 with the piston in this condition, air flow through annular passage 31B, housing passage 33A, and annular passage 31E, produces an unbalanced force in the small valve chamber at the right end of slidable plunger 32. The pressure thus applied .sets against the atmospheric pressure in the chamber at the left end of the plunger to force it to the left. With slidable plunger 32 in the extreme left hand position, air supplied at inlet 22 flows through annular passage 31B, through the chamber defined by reduced diameter portion 32A, and through annular passage 31C and passage 34, into chamber 36. The air being confined under pressure in chamber 36 forces piston 38 downward against spring force 42. Pneumatic piston 38 continues its downward stroke until the upper surface of piston extension 39 passes downward below the lower transverse opening of housing passage 33C within charnber 37. The right hand chamber lof slide valve 30 is then suddenly vented to atmosphere through annular passage 31E, housing passage 33C, and housing chamber 37 which is vented through atmospheric vent 24. Atmospheric pressure at the right end of valve 30 results in yan unbalanced force acting on the letf end of the plunger 32 which causes the plunger to immediately move toitsl thereby completing a reciprocating cycle of the pistonwhich will continue automatically, indefinitely, as long as air under sufficient pressure is supplied at inlet 22.

Hydraulic pumping action is derived from the recprocating motion of pneumatic piston 38 by causing hydraulic plunger 80 which is attached to the piston to reciprocate within hydraulic chamber 84. The reciprocating plunger 80 alternately draws hydraulic fluid 81 through passage 18 and check valve 86, into chamber 84, and forces the hydraulic fluid under pressure out of chamber 84, through check valve 88, and into flexible tubing 12 toward the -compression tool. It should be noted that as used herein, hydraulic fluid denotes the illustrated liquid such as hydraulic oil although the system is not necessarily limited to liquid force transmitting media. Chamber 84 is sealed from the interior of cylinder 40 by a plunger bushing 82.

Under normal operating conditions the chamber 84 will be filled with hydraulic fluid. As the plunger rod 80 descends, the chamber volume decreases and the fluid pressure increases, thereby unseating the check valve 88 and permitting 'the pressurized fluid to flow to the tool 10 through tubing 12. As the chamber volume increasesV ing portion of the pump 14, together with lower housing A fluid passages 91A, 91B, vand 91C, provides means for the return flow of hydraulic fluid and the equalizing of pressures between tubing 12 and reservoir 16, when the pump is at rest and reservoir inlet 26 has been` ventedl to atmospheric pressure. The valve assembly comprises a needle valve piston 92 having a needle plunger 93 and a central fluid passage 94, and two separate sliding valve seat portions 96 and 98 respectively, each of the latter including portions of confluent central passage 100. A spring 102 biases sliding Valve seats 96 and 98 to the right, against the housing of the valve assembly within annular fluid passage 104. Passage 104 in turn opens into pump housing passage 91C.

When the pump is in operation, high pressure fluid within tubing 12 passes through lower housing passage 91B and through central passages 100 and 94, and acts on the right end area of sliding valve seat 96 to force it to the left where it seats against shoulder 97; the fluid similarly acts on piston 92 to force it to the left where it seats needle plunger 93 against the opposed lshoulder portion of sliding seat 98. Fluid access from central passage to annular chamber 104 which surrounds piston 98, and to chamber 105 which surrounds piston 96, is thus blocked, and fluid flow between high-pressure fluid passage 91B and reservoir-pressure fluid passages 91A and 91C is prevented.

When the pump is at rest, high pressure fluid leakage through central passage 94, chamber 184, and reservoirpressure passage 91C, drops the fluid pressure on the surface of piston 92 sufficiently to permit spring 95 to unseat the needle plunger 93. This permits fluid flow from central passage 190 through chamber 104 and through passage 91C back to the reservoir 16 through the upper portion of passage 91A. Further drop in pressure in central passage 100 allows spring 102 to unseat sliding seat 96 from shoulder 97, thereby permitting direct flow of high pressure fluid from tubing 12 through passage 91B and chamber 105 directly into the reservoir through passages 91A and 18.

With the pump at rest, pressure equalization between tubing 12 and passage 18 continues through passages 91B and 91A until equilibrium is reached. It may be seen that equalization may be a two-way process, and that as fluid flow through these passages in one direction reduces the pressure in tubing 12 to the pressure in the reservoir 16, a rise in the reservoir pressure will be transmitted, by fluid flow in the opposite direction, to the tubing 12. Thus, while the pump is at rest and inlet 26 is vented to atmospheric pressure, the hydraulic pressure in tubing 12 will be essentially atmospheric; when air at a given pressure greater than atmospheric is applied to inlet 26, the pressure in tubing 12 will be raised to substantially that given pressure; and, when the pump is in operation, the pressure in tubing 12 will be raised to the pressure developed within chamber 84 by hydraulic plunger 80.

The two-way air valves 50 and 51 of the control system of this invention, illustrated in detail in FIGURE 3, may be seen to be essentially similar to the slide valve 30 contained in the pump housing, although they are not adapted for automatic reciprocation. Each valve contains a sliding plunger having a reduced diameter central portion 111, and a plurality of annular air passages 112A, 112B, 112C, 112D and 112E, in the valve housing. Endmost passages 112A and 112B are control passages connected through tubing 74 and 76 to control valves 54 and 56 respectively (or in the case of valve 51 to control valves 55 and 56), to control the position of the sliding plunger 110. The two valves 50 and 51 are identical, and corresponding parts of valve 51 have been designated, as previously, by primed reference numerals.

With both valve plungers in the extreme right-hand position shown in FIGURE 3, air pressure supplied from the source 60 through tubing 77 is completely cut ofl at valve inlets 62 and 62 which are blocked by the plungers 110 and 110. Pneumatic'passages 70 and 70 are each vented to atmospheric pressure, as in valve 50, through annular valve passage`112C, the chamber defined by the reduced diameter portion 111 of the plunger 110, annular passage 112D, and exhaust port 72. Air is not being supplied to pump 14 or to reservoir 16, and the pump is accordingly at rest and the iluid in the reservoir is at atmospheric pressure. Annual passages 112A, 112B and 112E are interconnected by tubing, or similar air passage means 114, which permits pressurized air from annular passage 112B to be transmitted through passage 112A to exert pressure on the left end of the plunger 110. Each plunger is thus maintained continuously in its right hand position. The two two-way valves, in this position, place the system as a whole in open condition, with the jaws 20 of the tool in fully opened position for receiving an article to be crimped between them.

The next position of the system as a whole, after the open condition, is hold condition, in which air pressure is applied through the valve 51 to the reservoir only, in order to raise the hydraulic pressure in the system to a rst value intermediate atmospheric and full crimping pressure. At this iirst pressure value the jaws close lightly, to hold an article inserted between them without crimping it. To apply air pressure to the reservoir through tubing 70', plunger 110 must be moved to the extreme left hand position in valve 51 to connect air inlet 62 to outlet 68 through annular passage 112B', around the reduced diameter portion 111' of the plunger 110 and through annular passage 112C. Movement of the plunger is accomplished by depressing the plunger 61 of control valve 55 against the spring 65. This unseats the plunger valve portion 63 from valve housing seat 67 and vents the connecting tubing 75 to atmospheric pressure through atmosphere vent port 69. This in turn reduces the pressure in the valve chamber at the left end of plunger 110 to atmospheric pressure, which unbalances the air pressure forces acting within the valve and allows the air conned in the small space at the right of the plunger to force it to the left.

Subsequent to placing the system in hold position With a connector gripped between the jaws of the tool, the system may be placed in crimp position to activate the pump in order to supply hydraulic crimping pressure to the tool. This may be accomplished by depressing the plunger of control valve 54 to force the plunger 110 of valve 50 to the left to in turn connect air inlet 62 to air outlet 68 and to supply operating air pressure to the pump 14 through tubing 70 as previously described.

After crimping pressure has been achieved and the connector is fully crimped, the system may be returned to release position to disengage the tool 10 for the connector, by depressing the plunger of control valve 56 to simultaneously move pistons 110 and 110 to the right by venting the valve chamber at the right and of each to atmospheric pressure in the manner described above.

The control valves 54, 55 and 56 are identical in construction and each is adapted to vent its attached tubing to atmosphere through a port 69 as in valve 55,

The invention has thus been described but it is desired to be understood that it is not confined to the particular forms or usages shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of the invention; therefore, the right is broadly claimed to employ all equivalent instrumentalities coming within the scope of the appendant claims, and by means of which objects of this invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to obtain these objects and accomplish these results.

I claim:

1. In a system including a fluid pressure-actuated compression tool having a fluid motor therein, the combination of: A source of pneumatic pressure; a hydraulic fluid reservoir; a source of hydraulic Huid pressure having a motor portion adapted to be selectively operated by pressure from said pneumatic pressure source, and a hydraulic compressor portion adapted to raise fluid from said reservoir to a given pressure when said motor portion is operated; means coupling said reservoir to said hydraulic compressor portion to supply uid thereto; means including pneumatically controlled valve means selectively movable to a rst position to apply pressure from said pneumatic pressure source to operate the motor portion of said hydraulic pressure source, and to a second position to reduce the pneumatic pressure applied to said motor portion; means coupling the output pressure of said hydraulic compressor portion to the fluid motor of said compression tool; means including pneumatically controlled valve means selectively movable to a rst position to apply pneumatic pressure to said fluid reservoir at a pressure lower than said given pressure, and to a second position to reduce the pneumatic pressure applied to said reservoir; pressure-actuated valve means connected in a uid passage means between said reservoir and said tool motor, adapted to permit passage of hydraulic pressure fluid from said reservoir to said tool motor at a pressure above a pre-selected value; said pressure-actuated valve means being adapted to maintain pressure in the said tool substantially equal to the pressure in the said reservoir when said hydraulic pressure source is not in operation.

2. The combination of claim 1 in the system therein set forth, further including control means for remotely operating said pneumatically controlled valve means; said control means comprising; a rst manually operable pneumatic exhaust valve coupled to one of said pneumatically controlled valve means and operable to produce a pressure differential therein for placing said one pneumatically controlled valve means in its said first position; a second pneumatically operable pneumatic exhaust valve coupled to the other of said pneumatically controlled valve means and operable to produce a pressure differential therein for placing the said other pneumatically controlled valve means in its said rst position; and a third manually operable pneumatic exhaust valve coupled to both of said pneumatially controlled valve means, and operable to move both of said pneumatically controlled valve means from the said rst position of each to the said second position of each.

References Cited by the Examiner UNITED STATES PATENTS 2,455,747 12/48 Fischer et al 60-51 2,573,993 1l/51 Sedgwick 60-51 2,877,624 3/59 Zoller 60-51 2,938,347 5/60 Sturgis 60-51 X FOREIGN PATENTS 830,997 3/ 60 Great Britain.

JULIUS E. WEST, Primary Examiner.

EDGAR W. GEOGHEGAN, Examiner. 

1. IN A SYSTEM INCLUDING A FLUID PRESSURE-ACTUATED COMPRESSION TOOL HAVING A FLUID MOTOR THEREIN, THE COMBINATION OF: A SOURCE OF PNEUMATIC PRESSURE; A HYDRAULIC FLUID RESERVOIR; A SOURCE OF HYDRAULIC FLUID PRESSURE HAVING A MOTOR PORTION ADAPTED TO BE SELECTIVELY OPERATED BY PRESSURE FROM SAID PNEUMATIC PRESSURE SOURCE, AND A HYDRAULIC COMPRESSOR PORTION ADAPTED TO RAISE FLUID FROM SAID RESERVOIR TO A GIVEN PRESSURE WHEN SAID MOTOR PORTION IS OPERATED; MEANS COUPLING SAID RESERVOIR TO SAID HYDRAULIC COMPRESSOR PORTION TO SUPPLY FLUID THERETO; MEANS INCLUDING PNEUMATICALLY CONTROLLED VALVE MEANS SELECTIVELY MOVABLE TO A FIRST POSITION TO APPLY PRESSURE FROM SAID PNEUMATIC PRESSURE SOURCE TO OPERATE THE MOTOR PORTION OF SAID HYDRAULIC PRESSURE SOURCE, AND TO A SECOND POSITION TO REDUCE THE PNEUMATIC PRESSURE APPLIED TO SAID MOTOR PORTION; MEANS COUPLING THE OUTPUT PRESSURE OF SAID HYDRAULIC COMPRESSOR PORTION TO THE FLUID MOTOR OF SAID COMPRESSION TOOL; MEANS INCLUDING PNEUMATICALLY CONTROLLED VALVE MEANS SELECTIVELY MOVABLE TO A FIRST POSITION TO APPLY PNEUMATIC PRESSURE TO SAID FLUID RESERVOIR AT A PRESSURE LOWER THAN SAID GIVEN PRESSURE, AND TO A SECOND POSITION TO REDUCE THE PNEUMATIC PRESSURE APPLIED TO SAID RESERVOIR; PRESSURE-ACTUATED VALVE MEANS CONNECTED IN A FLUID PASSAGE MEANS BETWEEN SAID RESERVOIR AND SAID TOOL MOTOR, ADAPTED TO PERMIT PASSAGE OF HYDRAULIC PRESSURE FLUID FROM SAID RESERVOIR TO SAID TOOL MOTOR AT A PRESSURE ABOVE A PRE-SELECTED VALUE; SAID PRESSURE-ACTUATED VALVE MEANS BEING ADAPTED TO MAINTAIN PRESSURE IN THE SAID TOOL SUBSTANTIALLY EQUAL TO THE PRESSURE IN THE SAID RESERVOIR WHEN SAID HYDRAULIC PRESSURE SOURCE IS NOT IN OPERATION. 